Elongated feed storage bags which extend horizontally on the ground surface have become a common replacement for the conventional vertical silos and bunker type storage of silage feed. The use of such bags requires considerable less capital cost, and they are capable of storing large quantities of feed with little spoilage. On the other hand, more work is usually involved in removing the feed as required from the bag and frequently more wastage occurs as compared to using common unloaders such as used in upright silos.
The most conventional manner of unloading the bag involves scooping the feed from an open end of the bag with a front-end loader or the like, and dumping the feed into a feed trough, a wagon or other carrier for moving the feed to an intake site of a feed system or a site directly available to the livestock. This process is not unlike that commonly used with bunker type storage of feed. The use of the storage bag, however, has a further disadvantage of having to cope with the loose plastic sheeting from the bag at the site of loading from the bag and its subsequent disposal.
There have been various proposals of machines for removing of silage stored in stacks on the ground or contained in bunkers or the like and simultaneously loading the removed silage into a wagon, but in the main, such machines are not generally in use because of their cost and the fact front-end loaders, which are usually readily available at cattle operations, are often capable of doing a relatively good job of breaking silage from the pile and moving it away as required. As indicated above, the removal of silage from a feed storage bag, on the other hand, presents problems somewhat different than those relating to bunker silos and the like because of the presence of the plastic sheet material, and this is certainly so in the case when a front end loader is being utilized. While attempts have been made to provide an unloading apparatus for use with feed storage bags, such as shown in U.S. Pat. No. 4,420,119, Dec. 13, 1983, to V. V. Johnson, as far as it can be determined, unloaders of this type, or of any type useful in unloading bags are not widely available on a commercial basis. It is believed that attempts to provide an apparatus to remove silage from feed storage bags has generally been unsuccessful due to the complexity of proposed self-contained machines which present a cost problem and to the fact they have not been capable of dealing with the variations in the size of bags utilized, and particularly, with the irregularities in the shapes assumed by such bags. The bags used for storing agricultural feed are purchased on the basis of desired diameter, and depending on a number of factors, such as the type of forage used, its moisture content at time of harvesting, and the initial compression achieved when filling the bag, the final cross sectional shape of the compacted mass of silage and size of the bag contents vary considerably after fermentation. Moreover, other features, such as the straightness of the horizontal axis of the elongated bag, vary from bag to bag as filled.